The Government has defined the National Science Challenges as an issue or opportunity that:Here's a few publicly available ideas I've presented earlier, to start off the brainstorming.
Is large, complex and important to New Zealand’s future
Has widespread agreement as to its national importance, and
Can potentially be solved or addressed by a scientific approach.
1) A Cook Strait Bridge; links the main islands with reliable infrastructure. No more ferries and the South Island power supply can run above the waves too.
2) A White Island power station using liquid hot magma to power Auckland.
3) Or, failing that solution to Auckland's energy crisis, a thorium reactor in Remuera.
UPDATE: Here's a new idea:
4) A series of canals and Archimedes screws between drought risk regions (too many to name) and New Plymouth in the north and West Coast in the south. Both are endless suppliers of fresh rainwater.